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Mechanical behavior and failure mechanisms of rock bolts subjected to static-dynamic loads

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International Journal of mining Science and technology 2024年第3期34卷 281-288页

作者： Hongpu Kang Guiyang Yuan Linpo Si Fuqiang Gao Jinfu Lou Jinghe Yang Shuangyong Dong ccteg Coal Mining Research InstituteBeijing 100013China State Key Laboratory of Intelligent Coal mining and Strata Control Beijing 100013China

This study explores the effects of dynamic and static loading on rock bolt performance a key factor in maintaining the structural safety of coal mine roadways susceptible to coal *** a housemade load frame to simulate various failure scenarios,pretension-impact-pull tests on rock bolts were conducted to scrutinize their dynamic responses under varied static load conditions and their failure traits under combined *** experimental results denote that with increased impact energy,maximum and average impact loads on rock bolts escalate significantly under pretension,initiating plastic deformation beyond a certain *** minor reductions in the yield load due to impactinduced damage,pretension aids in constraining post-impact deformation rate and fluctuation degree of rock ***,impact-induced plastic deformation causes internal microstructure dislocation,fortifying the stiffness of the rock bolt support *** magnitude of this fortification is directly related to the plastic deformation induced by the *** findings provide crucial guidance for designing rock bolt support in coal mine roadway excavation,emphasizing the necessity to consider both static and dynamic loads for improved safety and efficiency.

关键词： Rock bolt Pretension Static and dynamic load Impact

Critical review and functional safety of a battery management system for large‑scale lithium‑ion battery pack technologies

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International Journal of Coal Science & technology 2022年第3期9卷 1-17页

作者： K.W.See Guofa Wang Yong Zhang Yunpeng Wang Lingyu Meng Xinyu Gu Neng Zhang K.C.Lim L.Zhao Bin Xie azure mining technology ccteg 821 Pacifc HighwaySydneyNSW 2067Australia China Coal Research Institute Beijing 100013China China mining Products Safety Approval and Certifcation Center Beijing 100013China School of Mechanical Electronic and Information Engineering China University of Mining and TechnologyBeijing 100083China Beijing Tianma Intelligent Control technology Co. LtdBeijing 101399China Australian Institute for Innovative Materials Institute for Superconducting and Electronic MaterialsUniversity of WollongongInnovation CampusWollongongNSW 2500Australia

The battery management system(BMS)is the main safeguard of a battery system for electric propulsion and machine *** is tasked to ensure reliable and safe operation of battery cells connected to provide high currents at high voltage *** addition to efectively monitoring all the electrical parameters of a battery pack system,such as the voltage,current,and temperature,the BMS is also used to improve the battery performance with proper safety measures within the *** growing acceptance of lithium-ion batteries,major industry sectors such as the automotive,renewable energy,manufacturing,construction,and even some in the mining industry have brought forward the mass transition from fossil fuel dependency to electric powered machinery and redefned the world of energy ***,the functional safety considerations,which are those relating to automatic protection,in battery management for battery pack technologies are particularly important to ensure that the overall electrical system,regardless of whether it is for electric transportation or stationary energy storage,is in accordance with high standards of safety,reliability,and *** the system or product fails to meet functional and other safety requirements on account of faulty design or a sequence of failure events,then the environment,people,and property could be *** paper analyzed the details of BMS for electric transportation and large-scale energy storage systems,particularly in areas concerned with hazardous *** analysis covers the aspect of functional safety that applies to BMS and is in accordance with the relevant industrial standards.A comprehensive evaluation of the components,architecture,risk reduction techniques,and failure mode analysis applicable to BMS operation was also *** article further provided recommendations on safety design and performance optimization in relation to the overall BMS integration.

关键词： Battery management system Functional safety Hazardous area Lithium-ion batteries Failure mode analysis Electric transportation Large-scale energy storage

Mechanical properties and energy evolutions of burst-prone coal samples with holes and fillings

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International Journal of Coal Science & technology 2024年第3期11卷 176-189页

作者： Yukai Fu Yongzheng Wu Junchen Li Penghe Zhou Zhuoyue Sun Jie He ccteg Coal mining Research Institute Beijing100013China Coal mining and Designing Department Tiandi Science and Technology Co.Ltd.Beijing100013China Coal mining and Designing Branch China Coal Research InstituteBeijing100013China Resource Engineering Department China University of Mining and TechnologyBeijing100083China

During the mining process of impact-prone coal seams,drilling pressure relief can reduce the impact propensity of the coal seam,but it also reduces the integrity and strength of the coal mass at the side of the ***,studying the mechanical properties and energy evolution rules of coal samples containing holes and filled structures has certain practical significance for achieving coordinated control of coal mine rockburst disasters and the stability of roadway surrounding *** achieve this aim,seven types of burst-prone coal samples were prepared and subject to uniaxial compression experiments with the aid of a TAW-3000 electro-hydraulic servo testing ***,the stress–strain curves,acoustic emission signals,DIC strain fields and other data were collected during the ***,the failure modes and energy evolutions of samples with varying drilled hole sizes and filling materials were *** results show that the indexes related to burst propensity of the drilled coal samples decline to some extent compared with those of the intact one,and the decline is positively corelated to the diameter of the drilled *** hole filling,the strain concentration degree around the drilled hole is lowered to a certain degree,and polyurethane filling has a more remarkable effect than cement ***,hole filling can enhance the strength and deformation resistance of *** drilling can accelerate the release of accumulated elastic strain energy,turning the acoustic emission events from low-frequency and high-energy ones to high-frequency and low-energy ones,whereas hole filling can reduce the intensity of energy *** experimental results and theoretical derivation demonstrate that hole filling promotes coal deformability and strength mainly by weakening stress concentration surrounding the drilled ***,the fillings can achieve a better filling effect if their elastic modulus and Poisson’s ratio are closer

关键词： Rock mechanics Coal Mechanical properties Hole filling Energy evolution

Longwall face roof disaster prediction algorithm based on data model driving

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International Journal of Coal Science & technology 2022年第1期9卷 151-166页

作者： Yihui Pang Hongbo Wang Jinfu Lou Hailong Chai Coal mining Research Institute Co. Ltd of CCTEGBeijing 100013China Coal mining and Designing Department Tiandi Science&Technology Co.LtdBeijing 100013China Coal mining Branch China Coal Research InstituteBeijing 100013China School of Energy and mining Engineering China University of Mining and Technology-BeijingBeijing 100083China

Hydraulic support is the primary equipment used for surrounding rock control at fully mechanized mining *** load,location,and attitude of the hydraulic support are important sets of basis data to predict roof *** paper summarized and analyzed the status of coal mine safety accidents and the primary influencing factors of roof *** work also proposed monitoring characteristic parameters of roof disasters based on support posture-load changes,such as the support location and support *** data feature decomposition method of the additive model was used with the monitoring load data of the hydraulic support in the Yanghuopan coal mine to effectively extract the trend,cycle period,and residuals,which provided the period weighting characteristics of the longwall *** autoregressive,long-short term memory,and support vector regression algorithms were used to model and analyze the monitoring data to realize single-point *** seasonal autoregressive integrated moving average(SARIMA)and autoregressive integrated moving average(ARIMA)models were adopted to predict the support cycle load of the hydraulic *** SARIMA model is shown to be better than the ARIMA model for load predictions in one support cycle,but the prediction effect of these two algorithms over a fracture cycle is ***,we proposed a hydraulic support load prediction method based on multiple data cutting and a hydraulic support load template *** constructed technical framework of the roof disaster intelligent prediction platform is based on this method to perform predictions and early warnings of roof disasters based on the load and posture monitoring information from the hydraulic support.

关键词： Data model Roof disaster Hydraulic support Characteristic parameter Intelligent prediction

Numerical analysis on the factors affecting post-peak characteristics of coal under uniaxial compression

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International Journal of Coal Science & technology 2024年第1期11卷 42-60页

作者： Zhiguo Lu Wenjun Ju Fuqiang Gao Taotao Du ccteg Coal mining Research Institute BeijingChina State Key Laboratory of Coal Intelligent mining and Strata Control(China Coal Research Institute) BeijingChina

The post-peak characteristics of coal serve as a direct reflection of its failure process and are essential parameters for evaluating brittleness and bursting *** the significant factors that influence post-peak characteristics can offer valuable insights for the prevention of coal *** this study,the Synthetic Rock Mass method is employed to establish a numerical model,and the factors affecting coal post-peak characteristics are analyzed from four perspectives:coal matrix mechanical parameters,structural weak surface properties,height-to-width ratio,and loading *** research identifies four significant influencing factors:deformation modulus,density of discrete fracture networks,height-to-width ratio,and loading *** response and sensitivity of post-peak characteristics to single-factor and multi-factor interactions are *** result suggested that feasible prevention and control measures for coal bursts can be formulated through four approaches:weakening the mechanical properties of coal pillars,increasing the number of structural weak surfaces in coal pillars,reducing the width of coal pillars,and optimizing mining and excavation *** efficacy of measures aimed at weakening the mechanical properties of coal is successfully demonstrated through a case study on coal burst prevention using large-diameter borehole drilling.

关键词： Post-peak behavior Synthetic rock mass Coal bursts Coal burst prevention

Mechanical behaviors of coal measures and ground control technologies for China's deep coal mines-A review

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第1期15卷 37-65页

作者： Hongpu Kang Fuqiang Gao Gang Xu Huaiwei Ren ccteg Coal mining Research Institute BeijingChina Coal mining Branch China Coal Research InstituteBeijingChina State Key Laboratory of Coal mining and Clean Utilization China Coal Research InstituteBeijingChina

This paper reviews the major achievements in terms of mechanical behaviors of coal measures,mining stress distribution characteristics and ground control in China’s deep underground coal *** three main aspects of this review are coal measure mechanics,mining disturbance mechanics,and rock support *** studies related to these three topics are reviewed,including the geo-mechanical properties of coal measures,distribution and evolution characteristics of mining-induced stresses,evolution characteristics of mining-induced structures,and principles and technologies of ground control in both deep roadways and longwall faces.A discussion is made to explain the structural and mechanical properties of coal measures in China’s deep coal mining practices,the types and dis-tribution characteristics of in situ stresses in underground coal mines,and the distribution of mining-induced stress that forms under different geological and engineering *** theory of pre-tensioned rock bolting has been proved to be suitable for ground control of deep underground coal *** use of combined ground control technology(*** support,rock mass modification,and destressing)has been demonstrated to be an effective measure for rock control of deep *** developed hydraulic shields for 1000 m deep ultra-long working face can effectively improve the stability of surrounding rocks and mining efficiency in the longwall *** ground control challenges in deep underground coal mines in China are discussed,and further research is recommended in terms of theory and technology for ground control in deep roadways and longwall faces.

关键词： Deep underground coal mine Mechanical behavior mining-induced stress mining-induced fractures Ground control for roadways Ground control for working face

Effect of dynamic loading conditions on the dynamic performance of MP1 energy-absorbing rockbolts:Insight from laboratory drop test

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International Journal of mining Science and technology 2023年第2期33卷 215-231页

作者： Jinfu Lou Fuqiang Gao Jianzhong Li Guiyang Yuan Mostafa Sharifzadeh ccteg Coal mining Research Institute Beijing 100013China State Key Laboratory of Coal mining and Clean Utilization Beijing 100013China Key Laboratory of Ministry of Education on Safe mining of Deep Metal Mines Northeastern UniversityShenyang 110819China

Energy-absorbing rockbolts have been widely adopted in burst-prone excavation support, and their serviceability is closely related to the frequency and magnitude of seismic events. In this research, the splittube drop test with varying impact energy was conducted to reproduce the dynamic performance of MP1rockbolts under a wide range of seismic event magnitudes. The test results showed that the impact process could be subdivided into four distinct stages, i.e. mobilization, strain hardening, plastic flow(ductile), and rebound stage, of which strain hardening and plastic flow are the primary energy absorbing stages. As the impact energy per drop increases from 8.1 to 46.7 k J, the strain rate of the shank varies between 1.20 and 2.70 s^(-1), and the average impact load is between 240 and 270kN, which may be considered as constant. The MP1 rockbolt has a cumulative maximum energy absorption(CMEA) of 31.9–40.0 k J/m, with an average of 35.0 k J/m, and the elongation rate is 11.4%–14.7%, with an average of 12.7%, both of which are negatively correlated with the impact energy per drop. Regression analysis shows that energy absorption and shank elongation, as well as momentum input and impact duration,conform to the linear relationship. The complete dynamic capacity envelope of MP1 rockbolts is proposed, which reflects the dynamic bearing capacity, elongation, and distinct stages. This study is helpful to better understand the dynamic characteristics of energy-absorbing rockbolts and assist design engineers in robust reinforcement systems design to mitigate rockburst damage in seismically active underground excavations.

关键词： Energy-absorbing rockbolt Dynamic performance Drop test Residual elastic energy(REE) Energy absorption rate(EAR) Dynamic capacity envelope

Dynamic impact experiment and response characteristics analysis for 1:2 reduced-scale model of hydraulic support

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International Journal of mining Science and technology 2021年第3期31卷 347-356页

作者： Huaiwei Ren Desheng Zhang Shixin Gong Kai Zhou Chenyang Xi Ming He Tijian Li ccteg Coal mining Research Institute Beijing 100013China mining Design Ilnstitute China Coal Research InstituteBeijing 100013China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

It is significant to research the impact resistance properties of hydraulic support due to its key support role in the fully mechanized mining ***,it is difficult for the entire hydraulic support to implement the impact experiment underground and analyze the response ***,a dynamic impact experiment for the entire hydraulic support was proposed in this paper,where a 1:2 reducedscale model of hydraulic support was designed and its response characteristics under dynamic impact load were ***,a comprehensive monitoring scheme was proposed to achieve an effective monitoring for dynamic response of hydraulic ***,a multi-scale impact experiment was carried out for the entire hydraulic support and dynamic behaviors of hydraulic support under the multi-scale impact load were revealed by experimental *** a dynamic impact experiment of the entire hydraulic support was simulated in ADAMS with the same experiment conditions,and the experimental and simulation data were verified ***,the characteristics of energy conversion and dissipation of the entire experiment system after impact were *** experiment results showed that the impact resistance properties of hydraulic support largely depended on the initial support conditions and different vertical rigidities affected energy distribution proportion of the entire support system.

关键词： Hydraulic support Impact experiment Characteristics analysis Dynamics simulation ADAMS

Formation mechanism and height calculation of the caved zone and water-conducting fracture zone in solid backfill mining

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International Journal of Coal Science & technology 2020年第1期7卷 208-215页

作者： Lei Li Fengming Li Yong Zhang Daming Yang Xue Liu School of Energy and mining Engineering China University of Mining and Technology(Beijing)Beijing 100083China China Coal Research Institute Beijing 100013China China Coal technology&Engineering Group(ccteg)Central Research Institute Beijing 100013China College of mining and Geomatics Engineering Hebei University of Engineering.Handan 056000China

To study the heights of the caved zone and water-conducting fracture zone in backfill mining,the failure mechanism of strata during backfill mining was analyzed,and a method for determining the heights of the two zones was proposed based on key strata *** movement and failure regularity of the strata above the backfilling panel were revealed through numerical *** the geologic conditions of the CT101 backfilling panel,the height of the fracture zone was determined using the proposed method along with empirical calculation,numerical simulation,and borehole *** results of the new calculation method were similar to in situ *** traditional empirical formula,which is based on the equivalent mining height model,resulted in large errors during *** findings indicate the reliability of the new method and demonstrate its significance for creating reference data for related studies.

关键词： Backfill mining Strata failure Key strata Heights of caved and fracture zones